Improved electrical machine



UNITED STATES PATENT OEEICE.

H. JULIUS SMITH, OF BOSTON, MASSACHUSETTS.

IMPROVED ELECTRICAL MACHINE.

Speclicarion forming part of Letters latcut No. 93,563, dated August 10,1&6).

To /LZZ whom. t ntf/,y concern.-

Be it known that I, H. JULrUs SMITH, of Boston, in the Stat-e ofMassachusetts, have invented an Improved Electrical Machine; and I dohereby declare the following to be a full and correct description of thesame, reference being had to the accompanying drawings, in which- Figurel isa vertical section of my electrical machine, showing the collectors.Fig. 2 is a top view of the machine with the cov-ei removed. Fig. 3 is avertical section, showing the cushions or rubbers. Fig. 4 is a top viewwith the cover and other part-s broken.

The object of this invention is the production 0f an electrical machineconstructed with especial reference to portability and to working in allconditions of the atmosphere. It is designed more especially forigniting charges of powder by means of the electric spa-rk which itevolves.

lt is well known that the electrical machine as commonly constructed ofglass becomes wholly inefficient in a damp atmosphere such as prevailsin tunnels andmines. This is due to the 4fact that glass so very readilycondenses moisture upon its surface in the form of a continuous film.Vulcanite, on the contrary, does not so readily condense moisture, nordoes it condense moisture in the form of a film, but, rather, in theform of detached drops.

My machine consists of an outer covering` or shallow box containing aframe-plate, C, a Leyden jar or condenser, B, a generatingplate, D, anddevices for operating the gener ating-plate and condenser in connection.The frame-plate, the condenser, and the generating-plate are placedparallel to each other and parallel to the sides of the box, as shown.

The condenser B is connected to the frameplate C by four posts, l, 2, 3,and The generating-plate D lies between the condenser and frame-plate,and is revolved ou its axis E by means of the handle or crank F. Thisaxis E passes tightly through the stuiiing-box G, which may be made tograsp the axis more or less tightly by means of the packing-screw H. Theother end of the axis has its bearing in a small hole sunk in the outervulcanized plate of the condenser. The generatingplate D revolvesbetween two cushions, land K, the surfaces of which are coated with anamalgam, as is usual with electrical machines. The cushions are providedwith flaps, one of which is shown at M, Fig. 2. These flaps serve toprevent the electricity from escaping from the generating-plate D untilthe excited portion of its surface arrives in the neighborhood of thecollectors P, which are serrated strips of metal placed one on each sideof the plate D, as seen in Fig. 2, and both collectors are attached toand in metallic connection with the frame-post 4, and by it are broughtinto connect-ion with the inner plate or surface, r, of the Leyden jaror condenser. The twoouter plates or surfaces, s s', ofthe condenser arein metallic connection with the post 2 and also with the cushions l andK by means of post3.

The inner plate, r, connects with post 1 as well as with post 4. Y

The condenser B is constructed in the following manner: When thevulcaniteis in a plastic state, upon alayer of vulcanite is placed alayer of tin-foil. Over the layer of tin-foil there is placed a secondlayer of plastic vulcanite, and then a second layer of tin-foil. A thirdlayer of plastic vulcanite, a third of tinfoil, and a fourth ofvulcanite complete the jar or condenser. The first and third layers, ss, of tin-foil form the outer surfaces of the condenser, the middlelayer, r, forming the inner surface. Care must be taken that thediameter of the tinefoil plates be less thanthat of t-helayer of plasticrubber, excepting a small projection from each tin-foil plate, intendedto A connect with the posts of the frame. The condenser thus made up isthen submitted to the baking or vulcanizing process, at the end of whichit becomes hard and rigid. lts surfaces s, s', and r will forever remainin a perfectly dry condition. The posts l, 2, 3, and-eL are now screwedinto the condenser B, postsl and 4, as before stated, connecting withthe inner surface, r, while posts 2 and 3 connect with the outersurfaces, s s.

To the outer casing, A, are attached two knobs, V and WV. These knobsare electrodes or paths for the discharge of the electricity when theyare brought into contact with the inner and outer surfaces, r and s s',of the condenser, which is done by turningthe handle of the machinebackward a little until the postl comes into contact with a projectionfrom the knob V, and the post 2 comes into contact with the projectionfrom the knob WV.

There is a stop, vX, which serves to prevent the frame-work of thenrachine from revolving by the action of the crank, except through asmall arc. The post 1 is limitedin itsi'orward motion by the stop X andin its backward 1no lion by the projection from the knob V.

The casing A is made of vulcanite. rIwo forms of casing are shown in thedrawingsone a box in halves, which are screwed together, with a packingof soit rubber or other air-tight material between them, (seen in Fig.1;) the other a box with a cover, as shown in Fig. 3, having a rubberband placed over and around the outer edge. I prefer ille iirstdcscribed.

The operation of the machine is as follows: By turning thc crank F thegenerating-plate is revolved between the cushions I and K. Theelectricity generated is collected by the collectors P l?, and from themcarried by post 4 to the inner surface, yr, of the condenser. Theopposite electricity, appearing atthe rubbers I K, is conducted fromthem by post 3 to the outer surlace, s s', of the condenser. Bycontinued turning ofthe crank the condenser may be charged sufficientlyto give aspark oi' three-eights or one-half an inch in small inachinesof five or six inches in diameter. rlhe yfirst motion ofthe crank turnsthe frame as well as the generating-plate until postlstrikes the stop X.Turning the crank backward brings posts 1 and 2 in contact with theknobs V and lV, when the condenser may be discharged. It isdesirablethatthc condenser be discharged by the posts 1 and 2 ratherthan by posts 3 and 4, which are used for charging, as the tendency toescape during accumulation is thereby avoided. The frame-plate and thegenerating-plate are both made of plasticrubber and vulcanized.

The capacity of a Leyden jar or condenser constructed of plastic rubberand metallic plates, as above directed, may be increased by addingsuccessive layers of metal and vulcanite. Such a'condenser will be ofuse for electrical purposes, independently of the generating apparatusherein described.

4 I claimi l. A generating-plate and a flat condenser placed parallel toeach other within the same casing, substantially as described.

2. A Leyden jar or condenser constructed of vulcanized rubber andmetallic plates, substantially as described.

3. So arranging the jar or condenser that the forward motion of thecrank to generate electricity and charge the jar moves the jar forwardthrough a small are, whereby its terininals are moved away from thedischargingknobs.

et. The device for discharging the jar by the retrograde motion of thecrank bringing the posts 1 and 2 into contact with the projections fromknobs V and IV.

5. Placing the firing-points of the condenser at a distance from thecollecting-points, substantially as described.

6. rIhe stop x, limiting .the forward movenient of the jar,substantially as described.

7. The combination of a generating-plate, a condenser, anda casing madeair-tight, as described, by packing or a rubber band, together withknobs in the casing and their projections, by which the condenser isdischarged, substantially as described.

The above specification of my said invention signed and witnessed atBoston this 21st day of June, A. D. 1869.

H. J ULIUS SMITH.

